Differential block and tackle



(No Model.)

- 0. R. JONES.

DIFFERENTIAL BLOCK AND TACKLE. No. 302,258. Patented July 22, 1884.

PETERS, Fhuloutlw n lm. wasmn tm DJ:

UNITED STATES CORNELIUS R. JONES, OF SYRACUSE, NEWV- YORK.

PATENT OFFICE.

DIFFERENTIAL BLO CK AND TACKLE.

SPECIFICATION forming part of Letters Patent No, 302,258, dated July 22,1884.

Application filed June 13, 1883. (N0 model.)

To aZZ whom it may concern:

Be it known that I, CORNELIUS R. JONES, of the city of Syracuse,Onondaga county, State of New York, have invented certain new and usefulImprovements in Differential Blocks and Tackle, of which the followingis a description.

The purpose of my invention is to obtain an efficient differential ropetackle and pulleys that can be changed to an ordinary block and tackle,with loosepulleys that can be quickly overhauled, and again readilychanged-to differential for heavy lifting, so that it can be used foreither purpose and as quickly overhauled as an ordinary tackle-block. Ialso form the grooves of the first and last sheaves with ribs orprojections that securely hold the rope from slipping. I attain theseobjects by the mechanism illustrated in the accompanying drawings, inwhich Figure 1 is a section cut vertically through the block. Fig. 2 isa side view of the block and tackle; Fig. 3, sheaves b and d detach withclutch c; Fig. 4, section of sheave d on line A B, Fig. 1.

Similar letters refer to like parts in all the figures.

I employ in my improved tackle-block three or more sheaves of differentdiameters, corresponding with the take-up of the rope, so as to equalizethe strain thereon, for which purpose they are proportionedsubstantially as follows, which I have found most efficient forpractical results. Divide the diameter of the large sheave a into tenequal parts, and make the sheave cl seven of these parts in diameter.Then divide the three parts of dif ference between a and (1 into fiveparts, and add three of these to the seven before named for the diameterof the center sheave, I). These sheaves are contained in a shellcomposed of metal straps, as shown in the drawings, but maybe otherwiseconstructed, if desired. The largest sheave a is united with the nextsheave b. In the face of the sheave b, nextthesheave d, there isa'recess, 0, formed to receive within it a clutch, 0, (see Fig. 3,)having any convenient number of radiating arms, (three are shown in thedrawings, but I prefer a greater number.) Upon the face of the lastsheave (1 there is a similar recess, (1, into which the clutch c entersto unite the sheaves, and is withdrawn into sheave b to release sheaved.

Other intermediate sheaves can be added between 12 and d to increase thepower of the differential block and tackle. The sheaves are centered andturn 011 apin, e, that unites them to the cheeks of the block or sidestraps. This pin 6 has a movement endwise, governed bya lever, f,pivoted to the cheek of the block to which the pin 6 is connected. Theclutch c is held in place by the pin, on which itloosely turns. by meansof a shoulder turned on the pin, against which it comes, and is held bya thimble, e, that is slipped onto the end of the pin, and there keyed,(see Fig. 1,) so that when the pin 6 is moved endwise by the lever f theclutch o is moved into or out of the recess d to clutch or relieve thesheave cl. Opposite the groove in the large sheave a there is a recessin the horizontal strap of the block, that receives a small pulley, h,preferably made of some elastic material,which enters the groove of the.sheave a, to guide and hold the rope in the groove. A similar pulley, h,is in like manner placed in the groove of thelastsheave d, for a likepurpose.

In the grooves of the sheaves a and d, above named, there are ribs i,placed alternately on each side at intervals to correspond with thetwist of the rope in the tackle used, so as to fit into the intervalsbetween the strands of the rope to secure it from slipping, while theyare so formed as to freely deliver the rope from the groove withoutbinding. The lower block, 7c, is formed, in the usual way, with loosesheaves to correspond with the upper block and carry the bights of therope. Iuse in these blocks an endless rope tackle, and for heavy liftingrun it off the large sheave onto the small one, the sheaves of the upperblock being clutched together and the power increased by the number ofthe sheaves united. Thus rigged, the weight lifted will remain suspendedat any point it is raised to, and form a safety-lift.

For quickly overhauling the tackle, the clutch c is removed from sheavecl, when the blocks can be as readily and speedily drawn apart as anordinary double lift tackle. By knotting the rope or otherwise stoppingit at the point where it runs onto the small sheave I 3. In combinationwith an endless rope, a differential block: and tackle, the ribs in thegrooves of the sheaves, as described, taking 15 Having thus described myinvention, I into the twist of the rope, as specified. c1aim- 4. In adifferential block, the sliding pin 6, 1. In a block and tackle, theclutch c and clutch c, and lever f, substantially as and for sliding pin6, for uniting; and detaching the the purposes specified. iglggies, asspecified, and foi the puiposesset CORNELIUS R. JONES.

2. The pin 0, having a shoulder thereon, the clutch c, and thimble e,constructed as above described.

(2, when it is nnclutched, it becomes an ordinary double block andtackle forli ght weight and quick hoisting.

Witnesses:

J. J. GREENOUGH, H. 1W1. CLEMENT.

